1. Field of Invention
The present invention relates to a plasma display panel (PDP). More particularly, the present invention relates to a driving electrode structure of the PDP for improving operation margin of driving voltage.
2. Description of Related Art
User demand for entertainment equipment is growing due to the rapid development of multimedia applications. Conventionally, the cathode ray tube (CRT) display, a type of monitor, is commonly used. However, the cathode ray tube display does not meet the needs of multimedia technology because it has a large volume. Many flat panel display techniques such as liquid crystal display (LCD), plasma display panel (PDP), and field emission display (FED) have been recently developed in response to the needs of multimedia technology. These display techniques can manufacture a thin, light, short and small monitor, and thus these techniques are becoming the mainstream technology for the future. Of these techniques, the plasma display panel (PDP) is attracting attention in the field of displays as a full-color display apparatus having a large size display area and is especially popularly for use in large-size televisions or outdoor display panels.
A color PDP is a display in which ultraviolet rays are produced by gas discharge to excite phosphorus so that visible lights are emitted therefrom to perform a display operation. Depending upon a discharge mode, the color PDP is classified as an alternating current (AC) or a direct current (DC) type. In the AC-type PDP, an electrode is covered with a protective layer. The AC-type PDP has such characteristics that it inherently has a long life and a high brightness. Therefore, the AC-type PDP is generally superior to the DC-type PDP in luminance, luminous efficiency and lifetime. Generally, a 3-electrode type PDP including a common electrode, a scan electrode and an address electrode is employed in the AC-type PDP. The 3-electrode-type is directed to a surface discharge-type and is switched or sustained based on a voltage applied to the address electrode installed on a lateral surface of a discharge cell.
Common and scan electrodes disposed on an image display side substrate are generally formed of a transparent electrode made of a glass material for implementing a certain transmittivity of visual rays. The transparent electrode material is a semiconductor typically formed of ITO (e.g., a mixture of indium oxide In2O3 and tin oxide SnO2). The conductivity of the transparent electrode is relatively low in comparison with that of metal, and a fine conductive metal layer with narrow width is therefore added as the bus electrode on the transparent electrode to enhance the conductivity thereof.
In a color plasma display panel, fluorescent layers coated on an inner wall of each luminous cell convert the ultraviolet rays into light of three primary colors, such as red (R), green (G) and blue (B). A pulse writing voltage is applied to accumulate discharge charges for discharging on the surface of a protective layer covering the transparent electrodes during the light discharge process. Nevertheless, most accumulated charges are consumed at the moment of discharge, and thus a pulse sustaining voltage is needed for the luminous cells to provide required discharging charges for continuous luminance.
When the red, green and blue fluorescent layers are used in a plasma display panel, the sustaining voltage of each fluorescent layer has its driving range because of respective driving characteristics. If a conventional driving electrode structure with a bar transparent electrode and a strip bus electrode is employed, the sustaining voltage must be in the overlaid driving range of the three primary color cells to drive each respective color cell. The driving stability thus cannot be improved and the luminance conditions are consequently limited. For stable illumination, the conventional discharging-luminance structure must be more strictly fabricated, and the process windows for the structure are therefore limited. Hence, there is a requirement for enlarging the operation margin of the sustaining voltage.